Fix char comparison to EOF
Fix char comparison to EOF

`char c = fgetc(fptr); while (c != EOF) {...}` causes `pipe_mgr/core/pipe_mgr_cli.c:49:12: error: comparison is always true due to limited range of data type [-Werror=type-limits]`

Fix using `(!feof(fptr)) {...}`

Fixes https://github.com/p4lang/p4-dpdk-target/issues/13
p4lang/p4-dpdk-target,p4lang/p4-dpdk-target,p4lang/p4-dpdk-target,p4lang/p4-dpdk-target